Why Is It So Difficult to Study the Center of Our

Why is it so difficult to study the center of our galaxy?

A) Light from the center is lost in the glow of emission nebulae in this direction.
B) Interstellar dust blocks almost all light before it reaches Earth.
C) The exact position of the center is not known.
D) The center of the galaxy puts out very little radiation and is too dim to study.
E) The center of the galaxy is too far away for radiation to be detected by telescopes.